// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2009 Gael Guennebaud <gael.guennebaud@inria.fr>

/* NOTE The class IterationController has been adapted from the iteration
 *      class of the GMM++ and ITL libraries.
 */

//=======================================================================
// Copyright (C) 1997-2001
// Authors: Andrew Lumsdaine <lums@osl.iu.edu>
//          Lie-Quan Lee     <llee@osl.iu.edu>
//
// This file is part of the Iterative Template Library
//
// You should have received a copy of the License Agreement for the
// Iterative Template Library along with the software;  see the
// file LICENSE.
//
// Permission to modify the code and to distribute modified code is
// granted, provided the text of this NOTICE is retained, a notice that
// the code was modified is included with the above COPYRIGHT NOTICE and
// with the COPYRIGHT NOTICE in the LICENSE file, and that the LICENSE
// file is distributed with the modified code.
//
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// By way of example, but not limitation, Licensor MAKES NO
// REPRESENTATIONS OR WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY
// PARTICULAR PURPOSE OR THAT THE USE OF THE LICENSED SOFTWARE COMPONENTS
// OR DOCUMENTATION WILL NOT INFRINGE ANY PATENTS, COPYRIGHTS, TRADEMARKS
// OR OTHER RIGHTS.
//=======================================================================

//========================================================================
//
// Copyright (C) 2002-2007 Yves Renard
//
// This file is a part of GETFEM++
//
// Getfem++ is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.
// You should have received a copy of the GNU Lesser General Public
// License along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301,
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//========================================================================

#include "../../../../Eigen/src/Core/util/NonMPL2.h"

#ifndef EIGEN_ITERATION_CONTROLLER_H
#define EIGEN_ITERATION_CONTROLLER_H

namespace Eigen {

/** \ingroup IterativeLinearSolvers_Module
 * \class IterationController
 *
 * \brief Controls the iterations of the iterative solvers
 *
 * This class has been adapted from the iteration class of GMM++ and ITL libraries.
 *
 */
class IterationController
{
  protected:
	double m_rhsn;	  ///< Right hand side norm
	size_t m_maxiter; ///< Max. number of iterations
	int m_noise;	  ///< if noise > 0 iterations are printed
	double m_resmax;  ///< maximum residual
	double m_resminreach, m_resadd;
	size_t m_nit; ///< iteration number
	double m_res; ///< last computed residual
	bool m_written;
	void (*m_callback)(const IterationController&);

  public:
	void init()
	{
		m_nit = 0;
		m_res = 0.0;
		m_written = false;
		m_resminreach = 1E50;
		m_resadd = 0.0;
		m_callback = 0;
	}

	IterationController(double r = 1.0E-8, int noi = 0, size_t mit = size_t(-1))
		: m_rhsn(1.0)
		, m_maxiter(mit)
		, m_noise(noi)
		, m_resmax(r)
	{
		init();
	}

	void operator++(int)
	{
		m_nit++;
		m_written = false;
		m_resadd += m_res;
	}
	void operator++() { (*this)++; }

	bool first() { return m_nit == 0; }

	/* get/set the "noisyness" (verbosity) of the solvers */
	int noiseLevel() const { return m_noise; }
	void setNoiseLevel(int n) { m_noise = n; }
	void reduceNoiseLevel()
	{
		if (m_noise > 0)
			m_noise--;
	}

	double maxResidual() const { return m_resmax; }
	void setMaxResidual(double r) { m_resmax = r; }

	double residual() const { return m_res; }

	/* change the user-definable callback, called after each iteration */
	void setCallback(void (*t)(const IterationController&)) { m_callback = t; }

	size_t iteration() const { return m_nit; }
	void setIteration(size_t i) { m_nit = i; }

	size_t maxIterarions() const { return m_maxiter; }
	void setMaxIterations(size_t i) { m_maxiter = i; }

	double rhsNorm() const { return m_rhsn; }
	void setRhsNorm(double r) { m_rhsn = r; }

	bool converged() const { return m_res <= m_rhsn * m_resmax; }
	bool converged(double nr)
	{
		using std::abs;
		m_res = abs(nr);
		m_resminreach = (std::min)(m_resminreach, m_res);
		return converged();
	}
	template<typename VectorType>
	bool converged(const VectorType& v)
	{
		return converged(v.squaredNorm());
	}

	bool finished(double nr)
	{
		if (m_callback)
			m_callback(*this);
		if (m_noise > 0 && !m_written) {
			converged(nr);
			m_written = true;
		}
		return (m_nit >= m_maxiter || converged(nr));
	}
	template<typename VectorType>
	bool finished(const MatrixBase<VectorType>& v)
	{
		return finished(double(v.squaredNorm()));
	}
};

} // end namespace Eigen

#endif // EIGEN_ITERATION_CONTROLLER_H
